1. Field of the Invention
This invention relates to an improved liquid hydrocarbon diesel fuel and fuel additive for diesel engine fuel, and to a process of reducing air pollutants, hard carbon deposits in diesel engines and slime deposits in diesel fuel during storage.
2. Prior Art Relating to the Disclosure
A fuel additive comprising an aromatic metal free nitro compound such as picric acid and an iron salt of aromatic nitro acid such as ferrous picrate, dissolved in a solvent as methylated spirits of benzene, is disclosed in U.S. Pat. No. 2,506,539. This additive has several disadvantages which prevent its wide use. It has a very low flash point, is highly corrosive and is unstable. An attempt to overcome certain of these disadvantages is disclosed in U.S. Pat. No. 3,282,858 by the use of non-oxidizing compatible solvents for the aromatic metal free nitro compound and iron salts of the aromatic nitro acid. While this has been partially successful, the improved additive of this invention is much preferred.
In heavy duty diesel engines, such as those used in ships, locomotives, trucks and power generators, the combination of long idling times, variable fuel composition and frequent acceleration loads make the engine designer's work very difficult. He must compromise on several ideal designs and evolve a system which works adequately over a variety of operating conditions. When fuel is burned, several processes occur. At least three of these are important: (1) the ratio of air to fuel, (2) the degree of mixing at any particular place in the flame, and (3) the temperature. Depending on these three variables, the fuel may be either oxidized, cracked, or discharged unburned. Where there is an adequate supply of well-mixed air, oxygen is added to the fuel vapors producing successively more and more oxidized compound until the final state of minimum energy -- carbon dioxide and water -- is attained. If, on the other hand, there is not enough air to support this process in the reducing zone of the flame, the fuel breaks down as a result of the heat into smaller molecular units. This is the so-called cracking process which must occur with heavier types of fuel in order that they may become gases. However, if smaller units, ultimately carbon, slip through the visible flame zone, they are exhausted, giving a smoky exhaust containing carbon and smog-producing unburned hydrocarbons. Therefore, good mixing and atomization of the right portion of fuel and air with adequate heat present is vitally important. The additive of this invention improves the fuel combustion process in that it (1) improves fuel-air ratios by vigorously separating fuel droplets, giving far superior carburetion; (2) reduces or eliminates carbon deposits by more complete combustion; (3) promotes normal combustion chamber temperatures by removing heat-insulating carbon deposits by allowing more rapid cooling; (4) restores compression ratios as closely as possible to the engine's design allowing for normal motor wear; (5) reduces drastically crank case contamination by carbon, gum and varnish, giving longer oil life; (6) allows acids and other impurities to be more easily exhausted by reducing varnish, gum and carbon as binders; (7) reduces or eliminates injector fouling; (8) reduces piston ring and valve sticking; (9) increases horsepower; (10) achieves easier starting, smoother operation and faster pickup; (11) reduces or eliminates sparks from the exhaust; (12) reduces exhaust gas odors to non-objectionable levels; and (13) reduces air pollutants.